Process of aging and bleaching flour.



J. & S, ANDREWS.

PROCESS OF AGING AND BLEACHING FLOUR. (Applicatioxi filed Sept. 21, 1901.)

No. 693,207. PatentedTeb. ll, I902.

(No Model.)

"I (5 a. I: t

n kl i wjt Tasses v J VE HB 2 ing Flour, of which the following is a UNITED STAT es PATENT OFFICE.

JOHN ANDREVS ANT) SYDNEY ANDREWS, OE BELFAST, IRELAND.

PROCESS OF AGING AND IBLEACVHING FLOUR.

SPECIFICATION formingpart of Letters PatentNo. 693,207, dated February 11, 1902. I

Application filed September 21, 1901. Serial No. 76,038. (No specimens.)

To all who/1t it may concern:

Be it known that we, JOHN ANDREWS and SYDNEY ANDREWS, subjects of the King of Great Britain, residing at Belfast, in the county of Antrim, Ireland, have invented eerta'in new and useful Improvements in Treat- V specifloat-ion.

7 It has long been known that'fionr, semolina, and the like, hereinafter spoken of under the generic name of flour, if kept, for some time after grinding are greatly improved in quality. This improvement does not increase after a certain period, a deterioration then beginning.

Now our present invention is designed to bring about this improvement or conditionng 1m mediately after grinding, without havingfto wait, as above stated, and, further, not merely to bring about an improvement equal to that caused by keeping it for a long period, but a much greater improvement.

The invention consists, essentially, in subjecting the flour to the action of asuitable gaseous oxidizing agent, whereby n ascent exp en or i s equivalent isproduced or comes in contact with the flour. A very small quantity of the oxidizing agent suffices, so little, indeed, that the actual composition'of the flour, as shown by analysis, is hardly perceptibly altered. The plan we prefer is to pass the flour through various conveyors, whereby it is brought in contact with the gaseous oxidizing agent, and the drawings we herewith append show the apparatus which from long experience we have found to act best with air carrying a small quantity of gaseous peroxid of nitrogen, (N 0 We do not, however, limit ourselves to the use of nitrogen peroxid, as we have found that chlorin, bromin, and other gaseous compounds capable of liberating oxygen will act with more or less eificiency. Besides the above'reagents, ozone might be suggested; but we have found it is practically unworkable and its re- 'sults unsatisfactory or m'l, while it is more speaking of suitable oxidizing agents we do not includeozone, though in some chemical processes it does act as an oxidizing agent on. certain materials. Sulfuric and sulfhrous acid have also been suggested for bleaching grain and for disinfecting warehouses, ships holds, granaries, &c. which may contain flour. These two chemicals are, however, useless for flour, as they would spoil the tastewithout 6o improving it, and We also disclaim the use of such.

In our practice any of the other oxidizing agents mentioned, but preferably peroxid of nitrogen, is caused to act upon the flour by 6 forcing a current of air over orthrough the oxidizing agent employed, which current of air becomes impregnated with the oxidizing agent and is then brought in contact with p the flour to be improved. With regard to the quantity, a very small amount of the oxidizing agent is suffieient. Y

\Ve herewith append drawings of au'apparatus which we have found most suitable for use with nitrogen peroxid, the cheapest and most preferable reagent.

Figure 1 is a front elevation of the apparatus; Fig. '2, a plan of part thereof; Fig. 3, a cross-section of the cylinder on the dotted line Y Z. I

In thedrawings, A is an inclined hollow cylinder mounted in bearings 13' and rotated by means of a pulley C. In the interior of this cylinder are longitudinal ribs D, which agitate the flour, inserted at E, while assisting its passage down theeylinder. Each rib in .succession as itleaves the bottom during the rota- I tion of the cylinder carries up a small amount of flour, which when it has risen to about three-fourths of the height drops through the air in the cylinder to the bottom again. The flour is conveyedinto the interior of cylinder A through feed-hopper E, secured to the fixed worm-box F, inside whichis a worm conveyor Pt, mounted'on a hollow shaft G and rotated 5 by a pulley I-I.

J is jar or receptacle containing'nitric. acid, and Ka similar receptacle containing ferrous sulfate dissolved in water. These are arranged to deliver a regulated supply of nirec tric acid and ferrous sulfate, respectively, into a glass or ot-hervessel L, the liquid in which is maintained at a constant level by a siphonpipe M.

In a fifteen-sack-per-hour plant we use in practice commercial nitric acid, specific gravity 1.42, an eighty-ounce bottle; ferrous sulfate, two and one-fourth pounds, dissolved in about three pints of water, so as to make about eighty ounces. We now feed one of these into the other drop by drop-and proportion it so that they will last about sixty hours. In our first experiments We'used the nitric acid without the ferrous sulfate, and using commercial nitric acid and iron pipes we were enabled to get to some extent the same result as we now get with peroxid of nitrogen; but

the iron pipes were soon corroded, and when we used earthenware instead of iron the effect was almost m]. Almostany material, however, that will withdraw one atom of oxygen. from nitric acid can be used instead of ferrous sulfate; but we find that salt is very convenient and cheap.

l n thus (lescribingou r invention we wish to point out that it is based upon the principle of exposing the flour to a material which will give out nascent oxygen in the pores of the Hour, which nascent oxygen instantly attacks the oolnwing-matter of the Hour. Ordinary oxygen passed through has-not this effect, but only substances which, ccniingin contact with the flour, give out f rec oxygen to it, which had previously been in the combined state.

We declare that what we claim is- 1. The improvement in the process of aging posing it to an atmosphere containing a small quantity of gaseous nitrogen peroxid, substantially as set forth.

8. The improvement in the process of aging and bleaching flour which consists in gradu ally supplying to nitric acid, a material capable of taking from it one atom of oxygen and bringing the resulting gas into intimate contact with the flour, substantially as described.

4. The improvement in the process of aging and bleaching flour, which consists in gradually adding nitric acid and ferrous sulfate together in solution, and bringing the gas which results therefrom into intimate contact with the-flour, substantially as described.

In witness whereof we have hereunto signed our names, this 7th day of September, 1001, in the presence of two subscribing witnesses.

JOHN ANDREWS, SYDNEY ANDREWS.

Witnesses:

SIDNEY W. Don, .Arznnn'r (l. J. HENRI. 

